Marine Ecosystem Response in the Mediterranean EXperiment

https://mermex.mio.univ-amu.fr/

Description:

The second phase of the MERMEX program focuses on specific questions related to the impact of natural processes and anthropogenic factors on the functioning and state of Mediterranean marine ecosystems. A new and simplified organization into 3 major actions is proposed. The actions respectively deal with (i) the dynamics of contaminants and their impacts on ecosystems in the coastal zone (MERITE), (ii) the impact of dust deposition on the surface marine biogeochemistry (PEACETIME), and (iii) the impact of deep and intermedite water formations on the marine biogeochemistry and pelagic ecosystem functioning in an ultra oligotrophic context (PERLE). The proposed actions will be approached by a multidisciplinary consortium of scientists working together on observation and modeling. The strategy is designed to ensure that the knowledge acquired is used to understand the actual and future impact of these pressures across the Mediterranean.

Impact of contaminants - The MERITE (Marine ecosystem response to the input of contaminants in the coastal zone) action aims at investigating the fate of chemical contaminants and their impacts on the benthic and pelagic habitats, in specific coastal ecosystems, such as urbanized bays and contaminated fishing grounds in the western and central Mediterranean. The integrative approach is mainly based on in situ observational data (existing databases and targeted new data collection), experimental work and modeling research. Numerical modeling allow the examination of physical, biogeochemical and anthropogenic drivers in the studied coastal ecosystem, at the relevant time scales. The achievement of the objectives is based on an integrated study of biotic and abiotic compartments conducted in coordinated way in different sites (mainly located in the Gulf of Lion, Provence area, and in the Sfax Bay and Gulf of Gabes).

Impact of atmospheric deposition - The PEACETIME (Process studies at the air-sea interface after dust deposition in the Mediterranean) action proposes to study the fundamental physical, chemical and biological processes and their interactions at the atmosphere-ocean interface. The objective is to assess how these mechanisms impact, and will impact, the functioning of the marine biogeochemical cycles, the pelagic ecosystem and the feedback to the atmosphere. It will focus on a crucial mechanism forcing the biogeochemical coupling between the ocean and the atmosphere: atmospheric Saharan dust deposits. PEACETIME strategy is two-fold: (1) a cruise in the central Mediterranean Sea in May when strong dust deposition events usually occur and (2) substantial atmospheric and oceanic modeling developments (from 0-D to 3-D).

The PEACETIME project results from a joint reflection and a share of implementation between two components of the MISTRALS program: CHARMEX and MERMEX.

Impact of dense water formation - The PERLE (Pelagic ecosystem response to dense water formation in the Levant experiment) action aims at describing the formation and spreading of Levantine Intermediate Water (LIW), and determining its role on the distribution of nutrients and on the structuration of the planktonic ecosystems in the eastern Mediterranean. The LIW is one of the most crucial water mass of the Mediterranean: it contributes to most of the sub-surface water and salt transport between the eastern and western basins of the Mediterranean, it plays a key role in the deep convection both in the North Western Mediterranean and in the South Adriatic, and it fills nearly all the intermediate layer of the Eastern basin, where it is prone to vertical exchanges with the surface layer that supply nutrients to the photic layer and support a significant fraction of the primary production. Modeling at regional (Levantine basin) and large (Mediterranean) scales will be an important component of this action. It aims at improving the simulation of the LIW formation mechanisms and locations, and better assessing the effect of the regional physical conditions (including transient mesoscale structures) on the occurrence of blooms disrupting the ultraoligitrophic character of the Levantine basin.

The PERLE project results from a joint reflection and a share of implementation between two components of the MISTRALS program: HYMEX and MERMEX.

Coordinateurs : Xavier Durrieu de Madron (CEFREM, Perpignan) et Ivane Pairaud (IFREMER La Seyne/mer)

Responsable local :  Xavier Durrieu de Madron

Funding : Programme MISTRALS (Mediterranean Integrated STudies at Regional And Local Scales; http://www.mistrals-home.org/)